wil6210: interrupt moderation configuration update

Due to HW limitation, inter-packet gap timeout max value is 13 usec.
Update of current thresholds from 15 to 13 usec.

Signed-off-by: Vladimir Shulman <qca_shulmanv@qca.qualcomm.com>
Signed-off-by: Vladimir Kondratiev <qca_vkondrat@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>